Signaling system



Dec. 26, 1944.

G. H. DUHNKRACK SIGNALING SYSTEM Filed Nov. 25, 194s 2 ASheets-Sheet l Dec. 26, 1944. G VH. DUHNKRACK S IGNAL ING SYSTEM 2 Sheets-Sheet 2 .Filed Nov. 1125, 1943 NN bm.

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` f//s/l/EN TOR By 6. H. DUH/MRA CK ATTORNEY l Patented Dec. 26, 1944 UNITED STATES PATE OFF M21514 zgsessoy `sIGcsraLINGf SYSTEM. "George H. Duhnkraek, Maplewoc'd, Nif-l, assigner to Beli Telephone Laboratories, Incorporated;

New Yorkr N; Y.,.acorporato1r.of' NewYork Appnearionnovemter 25, 194s, sanar No. 511,678

" f3 claims. y (or. rial-21 This; invention relates to a cir-'cuit` arrangement.. and signal. controly meanstherefor, to. provide two-way polar simplex signalingv over a singlepair of wires interconnecting two4 remotely distant: attendants stationsv whereby two differ ent signals may beV transmitted in `one direction therebetween and three :different signals in the opposite direction. y

T he inventiony will be understood.v from. the: following description: when readI in connectione with thev accompanying drawings, Fig. `1 of which shows a radio channel' monitor control station having a. radio transmitter associated therewith and. Fig. 2` shows' adistant attendants station having; a radio receiver associated therewith,

. bothof. said stations (Figs. 1 and 2)" being inter- `transmiflter associated with. thats station, heA operates key 2II5-I which closes a circuit to.` operate relayi' Zilla* which can be tracedfi'rorn grourid,` conductor 201,. upper right winding.. of4 repeating coily 12118,. conductor"2ll9,..1ower: nia-kei contactl ofA key 205,.1ower backcontact of relay 21.0, windingrof relay.- 206, inner: back contact of relay zlgnpp'er make:` contact of' key 265i, conductor 236; lower right winding; ofv coilI 2.08, and` conductors ZILI and 21H2 to the"y non-grounded terminali 2-I13v of rectier.

21:4 and. through thev rectifier to the: opposite groundedterminal..221.52'V IthwillV bel understood that4 a battery on the proper: voltagev may bel substituted for the rectifier it desired.

The operation o'f'relay` 20B; at its contactsrZI,

tures which. restore to normal'.

ed positive battery I'Ill. When the foregoing simplex circuit is opened relay 22|' releasesV its y 222:. thereby preventingl the"y transmitter available lamp.v 223 lighting, when the contacts 22:4 ot relay 22|' close.. The release ofl relay 212| performs no` useful function. atthis time.

The release; of theA upper armatures of relay wt,- atithe distantfcontrol station. (Fig. l)`,A operatesrelay IlI-'I in al circuit which isv traced from battery, winding of relay IOT, contacts I 0`8 and L09-of relay IDI, contacts. Ill)` ot relay m5 and contactsJlI. ofxrelay |03" torgroundl R'elayIM closes.v a holding circuitV for normally operated ifelayZ-Iilf which caribe traced from; terminal 2'I3 of rectifier 214', winding of. relay 2| 1f, contacts-218 thereof,v and. contacts l 2 I6* ot relay 20B vto terminal' 2|5 of therectier; and at-its contacts 2|9f`cpens the simplex circuit extending to-the distantstation GFig. 11)" whichis normallyi closed'inlthe fllowing. circuit: ground", contacts zit-tici relay 2116, contacts 245i ofreIayf Z202 windings of'relayZZfI,` to the midpoint of the leftihandsideiof repeattion: (Fier rr; windineslefrelay It I1, contacts m2` 55 inl operating. causes` theoperation of` relay I I'2` in the following circuit: battery, 1`ef`t winding oi" impedance coil H3,` conductors II4' andi H5', contacts. I-Iliof relay II'I',.contact`s= IIT of'key H8, upper winding of. relay II2`, contacts IlIilofv key II`8, contacts I2I't'y of relay I`I`l'I,.concluctors I'ZI and` |22 and the: right-hand'winding ofv impedance coil II3 to ground. 1

Relay II2 at its contacts |23, locks itself operated, undercontrol offt'alkke'y I`='2"iI-, tobattery' and ground in series'witl'r impedance coil H3, and at its lower contacts. lights the calling lamp I2 5 and energizes; relay I2-B in. parallel: therewith which connect'si-thei buzzer |211 to battery and groundI through 'theimpedance coil I-*I^3, under control of the talk. key |245. thus giving the attendant at that station both ai visual andv audiblev calling signal..

'Rhefoperation ot talkkey I2Itb'y. the attendant releases Uothi oli these` signals' and connects. his

. telephone to theiline: and whena-the tallrkey'204 at thefcallingstation (Fig- 2)- is. operated', conversation.. between tlie two' attendants proceedsil l It will; bexrrotedi that in thetA preceding descripofa calli: from thestationatillig; 2 to the'station` atFg-.l 1 sigmaunew is accomplished `l'oy'oloen- 'ing the simprexl circuit: wni'cnzncrmally isv closed from positive'.l battery' tof the stationof. Fig; 11 to groundf at the station' of Fig.' 2.

In case-the" attendant at the station of" Fig'. 1

positive battery |06 from relay |0| and substitutes, at its contacts |29, negative battery |28 therefor and disconnects, at its contacts the ground connection to prevent the later operation of relay |01. The battery reversal through relay causes its upper armatures to release and its lower armatures to operate which, however, performs no useful function at this time.

Negative battery is thus applied to-the midpoint of the right-hand side of repeating coil |00 which passes over the two conductors of the line to the mid-point of the left-hand side of repeating coil 208 at the distant station, through the relay 22|, over contacts 246 of relay 2 20 and contacts 2|9 of relay 206 to ground which causes relay 22| to release its lower armatures and attract its upper ones. Release of the lower armatures opens contacts 232 thus releasingthe normally operated relay 2|`| but performs no other useful function. Operation of the inner upper armature, however, opens its contacts 233 thus preventing lamp 223 from lighting when the lower contacts 224 of this relay close, and by closing its contacts 225 completes a circuit to operate relay 2|0 which can be traced from terminals 2|3 of the rectifier 2 I4, conductor 2 I2, winding of relay 2|0, contacts 225 of relay 22|, and contacts 222 of relay 206 to ground.

Operation of relay 2|0 completes a circuit from terminal 2|3 of the rectier 2|4, contacts 225 of relay 2 l0, upper normal contacts of key 205, winding of relay, 221 in parallel with lamp 229, lower normal contacts of relay 205, contacts 228 of relay 2|0, to ground. Lamp 229 lights in this circuit and relay 221 operates to connect the buzzer to the rectifier 2 |4 in series with the righthand windings of repeating coil 208.

YWhen the distant calling key ||8 is released the lamp 229 is extinguished and the buzzer 230 is silenced.

When both talk keys |24 at the calling station and 204 at the called station are operated conversation between the two attendants over the line is possible.

From the foregoing it will be observed that a call signal from the radio channel control station (Fig. l) to the station of Fig. 2 is accomplished by connecting negative battery to the simplex circuit lat the calling station (Fig. l) to ground at the distant station (Fig. 2).

Remote control of the radio transmitter (Fig. 1) from the distant station (Fig. 2)

After the two attendants have agreed over the previously described intercommunicating circuit to give the attendant at the station of Fig. 2 control of the radio transmitter |30,associated with the station of Fig. 1, they release any operated keys thus restoring `the system to normal and the attendant at 'the station of Fig. 1 operates key |3| thereby causing operation of relay |05 which can be traced from battery |32, contacts |33and |34 of key |3| and Winding of relay |05. Relay |05 in operating completes a connection -from the radio transmitter |30 to the line over contacts |35 and |36 of key |3|, contacts |39 and i |40 of relay |0|, and contacts |4| and |42 of relay |05. Relay |05 in operating also closes its contacts |43 to connect a resistance l|44 in shunt to the condenser |45 in the repeating coil |00 to.

provide a direct current bridge across the line to the transmitter |30 for the purpose of operating certain relays therein, not shown.

Relay |05 in operating also opens its contacts |94 thus disconnecting positivey battery |06from f and open their previously closed contacts. 70,

.relighting lamp 223 as an indication that the the simplex circuit and at its contacts |48 substitutes ground therefor thus releasing the upper armatures of relay |0| which thereupon open their contacts |39 and |40 to disconnect the transmitter from the line pending control from the distant station. Further, operation of relay |05 opens its contacts ||0 thus preventing relay |01 from operating when contacts |09 of relay |0| are closed.

Connection of ground at contacts |48 of relay |05 in' the simplex circuit in series with relay 0| causes relay 22| at the distant station (Fig. 2) to release its lower armatures thereby opening contacts 232 thus releasing relay 2|1 and closure of contacts 224 causes lamp 223 to light as an indication that the distant transmitter is now under the control of the attendant at this station. This circuit is traced from terminals 2| 3 of the rectifier 2|4, conductor 2|2, lamp 223, contacts 224 and 233 of relay 22| and contacts 222 of relay 206 to ground. In the case just described it will be noted that the signal transmitted from the channel monitor control station (Fig. 1), to the distant station (Fig. 2) as an indication that the radio transmitter is available is accomplished by grounding both ends of the simplex circuit.

The attendant at the station of Fig. 2 now operates his fpress-to-talk key 234 thereby connecting his telephone transmitter 235 in series with the rectifier 2|4, the right-hand side of repeating coil 203, and relay 220, whereupon this Yrelay operates. This circuit can be traced from terminal 2|3 of the rectifier 2|4, conductors 2|2 and 2||, lower right winding of repeating coil 208, conductor 236, resistance 231, contacts 240 of key 234, contacts 239 of key 204, the telephone transmitter 235, contacts 238 of key 204, contacts 23| of key 234, winding of relay 220, upper right winding of repeating coil 208 and conductor 201 to ground'.

. Relay 220 in operating opens its contacts 246 thereby disconnecting ground from the simplex circuit including relay 22| and, by closing contacts 242, substitutes negative battery 24| therefor thus causing relay 22| to attract its lower armatures thereby opening "contacts 224 to extinguish the lamp 223, and by closing its contacts 232, operates relay 2|1 which relay in operating performs no useful function at this time. Application of negative battery to the simplex circuit causes relay |0| atv the distant control station to attract its upper armatures thereby closing its contacts |39 and |40 and connecting the left-hand side of repeating coil |00 to the radio transmitter |30 and due to the direct current bridge across the condenser |45 in the repeating coil, which includes resistance |44 and contacts |43 of relay |05, the transmitter is conditioned for transmission.

When the attendant atthe station of Fig. 2 finish-es talking he releases key 234 thereby releasing relay 220 which opens contacts 242 to disconnect negative battery 24| from the simplex and by closing contacts 246 substitutes ground therefor. lDue to the fact that ground is also connected at the other end of the simplex circuit, relays 22| (Fig. 2) and |0| (Fig. 1) release The release of relay 22| closes its contacts 224 thereby radio transmitter |30 at the distant station is still available but disconnected from the line L land the release of relay |0| opens its contacts V|39 and |40 to disconnect the transmitter |30 from the left-hand side of `repeating coil |00. The transmitter |30, however, remains under control of the push-to-talk key 234 as long as key |3| at the control station of Fig. 1 is operated.

Release of radio transmitter When the attendant at the station of Fig. 2 is nished with the radio transmitter he releases his press-to-talk key 234 which as before described opens the connection between the line L and the transmitter and then operates his intercommunicating signal key 205 to call in the distant attendant at the radio channel control station to request him to release key ||8 and free the transmitter.

At this time it will be noted that relays 22| and 2|1 are deenergized and released and. therefore as key 205 is operated and relay 206 responds, as described at the beginning of the description, ground is disconnected at contacts 222 of relay 206 to extinguish lamp 223 and to prevent operation of relay 2|0 when relay 22| operates and closes its contacts 225. Relay 206 in operating also opens contacts 2|9 thus disconnecting ground from relay 22| and by closing its contacts 243 substitutespositive battery 244 therefor in a circuit from battery 244, contacts 245 of relay 2| 1, contacts 243 of relay 206, contacts 24B of relay 220, windings of relay 22|, over the simplex circuit, through relay at the distant station to ground. Relay 22|.attracts its upper armature in this circuit which, however, performs no useful function at this time. i

At the distant control station, however, relay lill attracts its lower armatures thus closing its contacts |49 to energize relay |01 from ground at contacts of relay |03. Relay |01 in operating closes a circuit from battery and ground through impedance coil ||3, contacts H6 and |20 i of relay |01, contacts ||1 and ||9 of key ||8 to relay ||2 which lights the calling signal lamp |25 and sounds the buzzer |21. When the talk keys to both stations are operated, the attendants are able to converse with each other and the` attendant at the station of Fig. 2 may instruct the attendant at the radio channel control station (Fig. 1) to disconnect the radio transmitter which he does by releasing key |3| and when all of the keys at both stations are released, the circuit arrangement of the system is restored to its normal condition with the simplexlcircuit connected to positive battery at the station of Fig. 1 and the other end connected to ground.

It will be noted that whereas a calling signal was transmitted from the station of Fig. 2 to the station of Fig. 1, as rst described, by opening the simplex circuit when the radio transmitter is connected under control of -the station of Fig. 2, a calling signal from Fig. 2 to Fig. 1 is transmitted by connecting positive battery to the simplex circuit of Fig. 2 which circuit is grounded at Fig. 1.

What is claimed is:

1. In a radio communication control system, a radio transmitter, an attendants station associated therewith, a radio receiver and associated attendants station, aline interconnecting said station, a calling signal device at each station, a second signal device at the receiver station, signaling means at each station for controlling operation of the calling signal device at the other station, switching means at the transmitter station for preparing a connection between said radio transmitter and line and for actuating the second signal device at the receiver station, and l radio transmitter, characterized in this, that said' line comprises a single pair of wires having a simplex circuit superimposed thereon serially including a three-position polar relay at each station and normally connected to a source of positive potential at the transmitter station' and to ground at the other station, that control of the calling signal device at the transmitter attendants station by the signaling means at the receiver station when said switching means at the transmitter station is. not operated is effected by opening said simplex circuit at the receiver station and when the switching means at the transmitter station is operated by applying positive potential direct current tothe simplex circuit at the receiver station, that control of the calling signal device at the receiver station by the signaling means at the transmitter station is effected by applying negative potential direct current to the simplex at the transmitter station, that operation of the second signal device at the receiver station by operation of the switching device at the transmitter station is effected by completing a short-circuit around said simplex circuit, and that completion of the prepared connection between said radio transmitter and line at the transmitter station by the switching device at the receiver station is effected by applying negative potential direct current to the simplex at the receiver station.

2. In a signaling system, a pair of remotely opposed control stations, interconnecting means therebetween, each control station having means therein for transmitting speech to the other station over said interconnecting means and also having a plurality of individual direct current signal transmitting means each for affecting a different signal control' at the other station over said interconnecting means, each control station also having means therein for receiving and translating speech transmitted from the other station and having a plurality of individual direct current signal receiving means corresponding t0 the individual transmitting means at the other station and respectively responsive to signals transmitted thereby characterized in this, that said interconnecting means consists of a single pair of line wires, a, simplex circuit superimposed thereon and a three-'position polar relay in series with said simplex circuit at each control station.

current flowing in said channel, and means at each station for controlling the direction and flow of current in said channel.

GEORGE H. DUHNKRACK. 

